docs: def dump_yaml(testcase, yaml_file):
      """ dump HAR entries to yaml testcase
      """
      logging.info("dump testcase to YAML format.")
  
      with io.open(yaml_file, 'w', encoding="utf-8") as outfile:
          yaml.dump(testcase, outfile, allow_unicode=True, default_flow_style=False, indent=4)
  
      logging.info("Generate YAML testcase successfully: {}".format(yaml_file))